/// Processes a customer's orders in a streaming batch and produces a summary report.
///
/// Orders are loaded from the database and processed in parallel via a streaming
/// foreach; results are emitted downstream as each item completes rather than
/// waiting for the whole batch to finish.  Once all items have been processed the
/// report generator materialises the full result list.
///
/// Key DSL concepts demonstrated:
///   stream foreach   — processes each item and streams its result downstream as it
///                      completes; does not block waiting for the entire batch
///   buffer = N       — NodeChannel ring-buffer capacity for the stream edge
///   .output (input)  — DirectEdge: full materialised List<T> passed to generateReport
///
/// Context variables:
///   ctx.customerId — ID of the customer whose orders should be processed
graph streamingBatch {

  /// Loads orders from the database
  node loadOrders : OrderLoaderOperator {
    input {
      customerId = ctx.customerId
    }
  }

  /// Processes each order and streams results as they complete
  stream foreach processOrders : item in loadOrders.output.orders {
    buffer = 16
    node processItem : OrderProcessorOperator {
      input {
        order = item
      }
    }
  }

  /// Generates a summary report from all processed orders (materialized)
  node generateReport : ReportGeneratorOperator {
    depends_on = [processOrders]
    input {
      results = processOrders.output
    }
  }
}